The AHK place where you download it has some prewritten scripts for WOW. Or just Google it up autohotkey wow scripts. There's actually tons of prewritten AHK scripts out there. It's only advantage is it's free- multiboxing software has came lightyears ahead since then with ISBoxer.

What you need is the one for keyboard repeating. Then you can just delete what keys you don't want in notepad. Like mentioned above slaves usually just follow and have their own movement keys that aren't bound to your master's movement keys.